The invention is developed from a control apparatus of a fuel supply system for mixture-compressing, externally ignited internal combustion engines provided with a throttle member in the induction line and at least one catalytic converter situated in an exhaust line, the temperature of said converter being transmissible by means of a temperature sensor.
A control apparatus for a fuel supply system for an internal combustion engine is already known, in which a catalytic converter with a temperature sensor which measures the operating temperature is situated in the exhaust pipe, which control apparatus interrupts at least partially the supply of fuel or of the fuel-air mixture during unduly high catalytic converter temperatures. This, however, has the disadvantage that fuel is needlessly consumed before the fuel supply is interrupted and that exhaust gases are produced with a high proportion of toxic ingredients. In addition, with this known method the often desirable braking action of the motor during overrunning is impaired. Further, a control apparatus for a fuel supply system for an internal combustion engine is known, which furnishes such a large amount of air during overrunning of the engine that the supply of the fuel-air mixture is at least partly eliminated, which however results in the disadvantage, when such a control apparatus is employed in an internal combustion engine with a catalytic converter in the exhaust pipe, that the catalytic converter cools off during overrunning to below its lowest suitable operating temperature, and when normal fuel supply is reinstated after the overrunning is ended, the catalytic converter is at first too cold to reduce the noxious ingredients in the exhaust gas.